Immense and ever increasing amounts of solid trash, particularly of a municipal nature, are being generated each day. Disposal problems are growing with equal complexity. Conventional methods of refuse disposal, such as landfill or mere incineration, are becoming prohibitively expensive or creating serious pollution problems.
In particular, landfill areas are becoming fewer in number and further from the sites where the majority of the trash is generated. Incineration, because of national concern over the problems of air pollution, is being looked at with ever increasing skepticism.
Municipalities are, therefore, turning to techniques for processing solid wastes to recover, for resale or reuse, the values contained therein. This reduces the problems of pollution and helps offset the cost of processing the trash.
A general method of processing trash involves segregating the organic matter from the inorganics which includes metals, concrete, bricks, glass and the like.
With respect to the inorganic matter, ferrous materials may be separated magnetically prior to or following separation of the organics. The remaining inorganics are comminuted by crushing or grinding into particles of fine size. Some may be separated by screening and others by heavy media separations.
The tails from the treatment of municipal wastes are a mixture of finely divided sundry inorganic materials, the most valuable constituent of which is glass. The balance of inorganic materials include fine metal particles, bone, ceramics, egg shells, brick, rock, cementicious materials and the like. Unless recoverable, the glass in this tailing would have limited value as road fill as filler for asphalt or like applications.
It is known that amines serve as beneficiation reagents for the froth flotation of glass from the inorganic tails. In some instances, however, residue of solid waste is predominantly glass and it would be more economical to float the gangue of the mixture and leave the glass as the tailings. This is the subject matter of the instant invention.